Many varieties of packaged semiconductor devices and multi-chip modules (MCMs) are currently handled and shipped in molded plastic trays. Semiconductor manufacturers sometimes use molded plastic or metallic trays or pallets for processing of semiconductor devices. The majority of these devices are handled and shipped in trays or pallets because the package leads would be damaged if the packaged devices were handled or shipped in other container types. These trays, regardless of material type or intended use, all hold individual die, partially packaged or completely packaged devices in a regular matrix of individual cells. The trays come in several outline geometries and thicknesses and are sometimes known as "waffle packs." The most popular and widely used trays have a common outline and standard cell matrix patterns that are specified by widely accepted industry standards.
When trays for devices first came into regular use, semiconductor processing equipment was developed that removed individual packaged devices from the tray, moved the device through one or more processing steps and then returned the device to the same or a similar tray. This equipment is popularly known as "pick and place" equipment and is used throughout the industry. The pick and place method of device handling has a number of drawbacks. Each movement can introduce a potential for damage to the delicate device leads. Moving individual devices is also inherently slower than moving groups of devices. Establishing and maintaining alignment of the packaged devices so that the package can be presented in the correct orientation to the processing site is also a challenge. Equipment often requires customized hardware kits for each device package variation. Such kits are often expensive and require significant storage space when not in use.
Newer semiconductor processing equipment designs take advantage of the orderly and regular arrangement of devices in the trays or pallets to largely eliminate individual package handling. The entire tray or pallet is presented to the processing site and the individual packaged devices remain in the tray during processing. This method of processing is popularly known as "in-tray." In-tray processing is gaining acceptance in areas including attachment of solder balls to ball grid array (BGA) packages, encapsulation of semiconductor die in array packages, and device marking. In-tray processing is also gaining wide acceptance for device package lead and mark inspection. Unfortunately, the testing and burning-in of semiconductor devices is currently still restricted to pick and place processing. All existing processing equipment for the presentation of devices to an electrical test system or for the loading and unloading of devices into and from thermal or electrical stressing (burn-in) equipment is of the pick and place variety. These operations represent the highest potential for device lead damage. Electrical test equipment is extremely expensive and utilization rates suffer due to the inherent slowness of pick and place equipment handling individual devices.
Accordingly, a need exists in the industry for method for testing, burning-in, or otherwise electrically contacting semiconductor devices while in-tray. Such a method would reduce device lead damage and increase throughput as compared to current testing and burn-in methods.